CR50: define EMBEDDED_MODE=1 for code under cr50.
CR50: define EMBEDDED_MODE=1 for code under cr50.

EMBEDDED_MODE was missing from code compiled under
cr50/tpm2, which resulted in code under third_party/tpm2
and cr50/tpm2 inferring differing declarations for
a given type.

BRANCH=none
TEST=tests under test/tpm2 pass
BUG=chrome-os-partner:43025,chrome-os-partner:47524

Change-Id: I56935f5ae8fc45e6b7f71eb239b3e0c325086795
Signed-off-by: nagendra modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Reviewed-on: https://chromium-review.googlesource.com/325471
Commit-Ready: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Tested-by: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Reviewed-by: Vadim Bendebury <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec